Crew seating arrangement

Flight

The first launch attempt was
on July 20, 1999, but controllers aborted the launch at T-6 seconds, just
before main engine ignition, due to a data spike in hydrogen pressure data.
This problem was determined to be due to a faulty sensor and a second attempt
was on July 22, 1999. A lightning storm prevented launch during the 46 minute
window, and the launch was again scrubbed.

The again used super
lightweight external tank (SLWT) made its first Shuttle flight June 02,
1998, on mission STS-91. The SLWT is
7,500 pounds (3,402 kg) lighter than the standard external tank. The lighter
weight tank allowed the shuttle to deliver International Space Station elements
(such as the service module) into the proper orbit. The SLWT had the same size
as the previous design. But the liquid hydrogen tank and the liquid oxygen tank
were made of aluminum lithium, a lighter, stronger material than the metal
alloy used for the Shuttle's current tank. The tank's structural design had
also been improved, making it 30% stronger and 5% less
dense.

Columbia did not reach the planned orbit. Five seconds
after liftoff, an electrical short disabled one primary and one secondary
controller on two of the three main engines. In this event, the engines
automatically switched to their backup controllers. The engine igniters were
on, due to an excess build-up of hydrogen in the main engines. It was the
furthest in the countdown that a Space Shuttle launch countdown has ever been
held before engine ignition, which would have resulted in an abort by the RSLS
system. The short was later discovered to have been caused by poorly routed
wiring which had rubbed on an exposed screw head. This wiring issue led to a
program-wide inspection of the wiring in all orbiters. Concurrently, an
oxidizer post, which had been intentionally plugged, came loose inside one of
the main engine's main injector and impacted the engine nozzle inner surface
rupturing a hydrogen cooling line allowing a small leak. Because of the leak,
the engine's controller saw an increase in use rate of hydrogen. The controller
assumed the extra hydrogen was being burned in the engine (rather than being
leaked overboard as it actually was) and increased the oxidizer flow to
maintain the presumptive mixture ratio, resulting in a premature engine
shutdown near the end of the projected burn due to low liquid oxygen level.
Despite the premature shutdown, the vehicle safely achieved a slightly lower
orbit and was able to complete the mission as planned. This incident brought on
a maintenance practice change which required damaged oxidizer posts to be
removed and replaced as opposed to being intentionally plugged, as was the
practice beforehand.Backup controllers took over, but a further failure on
the backup controller bus would have resulted in engine shutdown and the first
ever attempt at an RTLS (Return To Launch Site) abort. To further complicate
matters engine 3 (SSME 2019) had a hydrogen leak throughout the ascent, causing
the engine to run hot. Controllers sweated as temperatures neared redline. The
hot engine's controller compensated as programmed by using additional liquid
oxygen propellant. The final result was that the shuttle ran out of gas - main
engine cut-off (MECO) was at 04:39
UTC, putting Columbia into a 78 km x 276 km x 28.5
degree transfer orbit. Columbia was 1,700 kg short of oxygen propellant and 5
meters/sec slower than planned. The
OMS-2 engine burn at 05:12
UTC circularized the orbit 10 km lower than
planned.

The RTLS abort mode was designed to allow the return of
the orbiter, crew, and payload to the launch site, Kennedy Space Center,
approximately 25 minutes after lift-off. The RTLS profile was designed to
accommodate the loss of thrust from one space shuttle main engine between
lift-off and approximately four minutes 20 seconds, at which time not enough
main propulsion system propellant remains to return to the launch site.An
RTLS can be considered to consist of three stages-a powered stage, during which
the space shuttle main engines are still thrusting; an ET separation phase; and
the glide phase, during which the orbiter glides to a landing at the Kennedy
Space Center. The powered RTLS phase begins with the crew selection of the RTLS
abort, which is done after solid rocket booster separation. The crew selects
the abort mode by positioning the abort rotary switch to RTLS and depressing
the abort push button. The time at which the RTLS is selected depends on the
reason for the abort. For example, a three-engine RTLS is selected at the last
moment, approximately three minutes 34 seconds into the mission; whereas an
RTLS chosen due to an engine out at lift-off is selected at the earliest time,
approximately two minutes 20 seconds into the mission (after solid rocket
booster separation).After RTLS is selected, the vehicle continues downrange
to dissipate excess main propulsion system propellant. The goal is to leave
only enough main propulsion system propellant to be able to turn the vehicle
around, fly back towards the Kennedy Space Center and achieve the proper main
engine cutoff conditions so the vehicle can glide to the Kennedy Space Center
after external tank separation. During the downrange phase, a pitch-around
maneuver is initiated (the time depends in part on the time of a space shuttle
main engine failure) to orient the orbiter/external tank configuration to a
heads up attitude, pointing toward the launch site. At this time, the vehicle
is still moving away from the launch site, but the space shuttle main engines
are now thrusting to null the downrange velocity. In addition, excess orbital
maneuvering system and reaction control system propellants are dumped by
continuous orbital maneuvering system and reaction control system engine
thrustings to improve the orbiter weight and center of gravity for the glide
phase and landing.The vehicle will reach the desired main engine cutoff
point with less than 2 percent excess propellant remaining in the external
tank. At main engine cutoff minus 20 seconds, a pitch-down maneuver (called
powered pitch-down) takes the mated vehicle to the required external tank
separation attitude and pitch rate. After main engine cutoff has been
commanded, the external tank separation sequence begins, including a reaction
control system translation that ensures that the orbiter does not recontact the
external tank and that the orbiter has achieved the necessary pitch attitude to
begin the glide phase of the RTLS.After the reaction control system
translation maneuver has been completed, the glide phase of the RTLS begins.
From then on, the RTLS is handled similarly to a normal entry.

The
primary objective of the
STS-93 mission was to deploy the Chandra X-ray
Observatory (formerly the Advanced X-ray Astrophysics Facility) with its
Inertial Upper Stage (IUS) booster. At its launch, Chandra was the most
sophisticated X-ray observatory ever built. It is designed to observe X-rays
from high energy regions of the universe, such as hot gas in the remnants of
exploded stars.In addition, crew members operated the Southwest Ultraviolet
Imaging System, a small telescope which was mounted at the side hatch window in
Columbia's middeck to collect data on ultraviolet light originating from a
variety of planetary bodies.

The Chandra X-Ray Observatory was composed
of three major assemblies: the spacecraft, telescope and science instrument
module.

The spacecraft module contained computers, communication
antennas and data recorders to transmit and receive information between the
observatory and ground stations. The on-board computers and sensors - with
ground-based control center assistance - command and control the observatory
and monitor its health during its expected five-year lifetime. The spacecraft
module also provides rocket propulsion to move and aim the entire observatory.
It contains an aspect camera that tells the observatory its position and
orientation relative to the stars, and a Sun sensor that protects it from
excessive light. Two three-panel solar arrays provide the observatory with
2,350 watts of electrical power and charge three nickel-hydrogen batteries that
provide backup power.

At the heart of the telescope system is the
high-resolution mirror assembly. Since high-energy X-Rays would penetrate a
normal mirror, special cylindrical mirrors were created. The two sets of four
nested mirrors resemble tubes within tubes. Incoming X-Rays will graze off the
highly polished mirror surfaces and be funneled to the instrument section for
detection and study. The mirrors of the X-Ray observatory are the largest of
their kind and the smoothest ever created. If the state of Colorado were the
same relative smoothness, Pike's Peak would be less than one inch tall. The
largest of the eight mirrors is almost four feet in diameter and three feet
long. Assembled, the mirror group weighs more than one ton. The High-Resolution
Mirror Assembly is contained in the cylindrical "telescope" portion of the
observatory. The entire length of the telescope is covered with reflective
multi-layer insulation that will assist heating elements inside the unit in
keeping a constant internal temperature. By maintaining a precise temperature,
the mirrors within the telescope will not be subjected to expansion and
contraction - thus ensuring greater accuracy in observations.

The
High-Resolution Camera will record X-Ray images, giving scientists an
unequaled look at violent, high-temperature occurrences like the death of stars
or colliding galaxies. The High-Resolution Camera is composed of two clusters
of 69 million tiny lead-oxide glass tubes. The tubes are only one-twentieth of
an inch long and just one-eighth the thickness of a human hair. When X-Rays
strike the tubes, particles called electrons are released. As the electrons
accelerate down the tubes - driven by high voltage - they cause an avalanche of
about 30 million more electrons. A grid of electrically charged wires at the
end of the tube assembly detects this flood of particles and allows the
position of the original X-Ray to be precisely determined. By electronically
determining the entry point of the original X-Ray, the camera can reproduce a
high-resolution image of the object that produced the X-Rays. The
High-Resolution Camera will complement the Charge-Coupled Device Imaging
Spectrometer, also contained in the science instrument module.The AXAF
CCD Imaging Spectrometer (ACIS) is capable of recording not only the
position, but also the color, or energy, of the X-Rays. The ACIS is made up of
10 charge-coupled device arrays. These detectors are similar to those used in
home video recorders and digital cameras, but are designed to detect X-Rays.
The ACIS can distinguish up to 50 different energies within the range that the
observatory operates. In order to gain even more energy information, two
screen-like instruments - called diffraction gratings - can be inserted into
the path of the X-Rays between the telescope and the detectors. The gratings
change the path of the X-Ray depending on its energy and the X-Ray cameras
record the color and position. One grating concentrates on the higher and
medium energies and uses the imaging spectrometer as a detector. The other
grating disperses low energies and is used in conjunction with the High
Resolution Camera. Commands from the ground allow astronomers to select which
grating to use.

On
STS-93, the Inertial Upper Stage helped propel the
Chandra X-Ray Observatory from low Earth orbit into an elliptical orbit
reaching one-third of the way to the Moon. The Inertial Upper Stage is a two
stage, inertially guided, three-axis stabilized, solid fuel booster used to
place spacecraft into a high-Earth orbit or boost them away from the Earth on
interplanetary missions. It is approximately 17 feet (5.2 meters) long and 9.25
feet (2.8 meters) in diameter, with an overall weight of approximately 32,500
pounds (14,714 kg).

Once on orbit, the Shuttle crew activated the
spacecraft power system, and controllers at the Chandra X-Ray Observatory
Control Center in Cambridge, MA, began activating and checking out key
observatory systems.Chandra controllers activated and checked out the
observatory's computers, activate heaters to control the temperature of
observatory systems and initiated venting of Chandra's imaging spectrometer.
Controllers also tested the system that would have placed Chandra in a safe
mode should an anomaly occurred after deployment and test communications links
between the observatory and the ground through Chandra's upper
antenna.Approximately five-and-a-half hours after launch, the Shuttle crew
tilts the Chandra and its Inertial Upper Stage up to 29 degrees. Chandra
controllers then checked radio communications links between the observatory and
the ground through Chandra's lower antenna. Following initial activation and
checkout of Chandra by the Operations Control Center, the Columbia crew
configured the Inertial Upper Stage for deployment, disconnected umbilicals
between the orbiter and payload, and raised the payload to its deployment
attitude of 58 degrees above the payload bay.Catherine
Coleman then deployed the observatory and its upper stage a
little over seven hours after launch before maneuvering the Shuttle to a safe
distance from Chandra.About an hour later the Inertial Upper Stage will
fire its first stage solid rocket motor for about two minutes, then coast
through space for about two minutes more. The first stage separated, and the
second stage fired for almost two additional minutes. This placed the
observatory into a temporary, or transitional, elliptical orbit peaking at
37,200 miles (59,854 km) above the Earth and approaching the Earth to within
174 miles (280 km).Chandra's twin solar arrays then were unfolded, allowing
Chandra to begin converting sunlight into 2,350 watts of electrical power to
run the observatory's equipment and charge its batteries.Next, the Inertial
Upper Stage separated from the observatory and Chandra's own propulsion system
gradually moved the observatory to its final working orbit of approximately
6,214 by 86,992 miles (10,000 by 140,000 km) in altitude. It took approximately
10 days and five firings of Chandra's own propulsion system to reach its
operating orbit.

The Southwest Ultraviolet
Imaging system (SWUIS) was based around a Maksutov-design
ultraviolet (UV) telescope and a UV-sensitive, image-intensified Charge-Coupled
Device (CCD) camera that frames at video frame rates. The Southwest Ultraviolet
Imaging System (SWUIS) was an innovative telescope/charge-coupled
device (CCD) camera system that operated from inside the shuttle cabin. SWUIS
was used to image planets and other solar system bodies in order to explore
their atmospheres and surfaces in the ultraviolet (UV) region of the spectrum,
which astronomers value for its diagnostic power.SWUIS made its first flight on
STS-85 in August 1997. On that
mission,
SWUIS obtained over 400,000 images of the Hale-Bopp
Comet at a time when the Hubble Space Telescope could not observe the comet
because it was lost in the glare of the sun. These images have already revealed
important insights into the comet's water and dust production rates as it left
the sun on its return to the Oort Cloud of comets, 10,000 times as far away as
Pluto.

The Shuttle Ionespheric Modification with Pulsed Local Exhaust
(SIMPLEX) payload activity researched the source of Very High Frequency
(VHF) radar echoes caused by the orbiter and its
OMS engine firings. The Principal Investigator (PI)
used the collected data to examine the effects of orbital kinetic energy on
ionospheric irregularities and to understand the processes that take place with
the venting of exhaust materials.

The Shuttle Amateur Radio
Experiment (SAREX-II) demonstrated the feasibility of amateur
short-wave radio contacts between the shuttle and ground-based amateur radio
operators.
SAREX also served as an educational opportunity for
schools around the world to learn about space by speaking directly to
astronauts aboard the shuttle via amateur radio.

The EarthKAM
payload conducted Earth observations using the Electronic Still Camera (ESC)
installed in the overhead starboard window of the Aft Flight Deck.

The
Plant Growth Investigations in Microgravity (PGIM) payload experiment
used plants to monitor the space flight environment for stressful conditions
that affect plant growth. Because plants cannot move away from stressful
conditions, they have developed mechanisms that monitor their environment and
direct effective physiological responses to harmful conditions.

The
Commercial Generic Bioprocessing Apparatus (CGBA) payload hardware
allows for sample processing and stowage functions. The Generic Bioprocessing
Apparatus  Isothermal Containment Module (GBA-ICM) is temperature
controlled to maintain a preset temperature environment, controls the
activation and termination of the experiment samples, and provides an interface
for crew interaction, control and data transfer.

The Micro-Electrical
Mechanical System (MEMS) payload examines the performance, under launch,
microgravity, and reentry conditions of a suite of MEMS devices. These devices
include accelerometers, gyroscopes, and environmental and chemical sensors. The
MEMS payload is self-contained and requires activation and deactivation
only.

The Biological Research in Canisters (BRIC) payload was
designed to investigate the effects of space flight on small arthropod animals
and plant specimens. The flight crew was available at regular intervals to
monitor and control payload/experiment operations.The objective of BRIC-11
was to investigate gravity-regulated gene expression by using Earth- and
space-grown seedlings. These studies represent a first step toward
understanding the effects of gravity on gene regulation. Arabidopsis was chosen
because it offers a number of advantages for molecular genetic studies. It also
allows the investigator to analyze the expression of thousands of genes
simultaneously by using a DNA "chip" technology.

The objectives of
Cell Culture Model, Configuration C (CCM-C) were to validate cell
culture models for muscle, bone, and endothelial cell biochemical and
functional loss induced by microgravity stress; to evaluate cytoskeleton,
metabolism, membrane integrity, and protease activity in target cells; and to
test tissue loss pharmaceuticals for efficacy.The experiment unit fitted
into a single standard middeck locker with the door panels removed. The unit
took in and vented air to the cabin via the front panel. The experiment was
powered and functioned continuously from prelaunch through postlanding. The
analysis module for
STS-93 was CCM Configuration C. It had a hermetically
sealed fluid path assembly containing the cells under study, all media for
sustained growth, automated drug delivery provisions to test candidate
pharmaceuticals, in-line vital activity and physical environment monitors,
integral fraction collection capabilities, and cell fixation facilities. The
fluid path and media were cooled by a 4-degree Celsius active cooling chamber
and associated cabling and driver circuitry. (This payload was formerly called
Space Tissue Loss, Configuration A.)

The GOSAMR experiment
attempted to form precursors for advanced ceramic materials by using chemical
gelation (disrupting the stability of a sol and forming a semi-solid gel).
These precursor gels will be returned to 3M Science Research Laboratories,
dried, and fired to temperatures ranging from 900 to 2,900 degrees F (482 to
1,593 degress Celsius) to complete the fabrication of the ceramic composites.
These composites will then be evaluated to determine if processing in space
resulted in better structural uniformity and superior physical
properties.

The Lightweight Flexible Solar Array Hinge (LFSAH)
consisted of several hinges fabricated from shape-memory alloys, which allow
controlled, shockless deployment of solar arrays and other spacecraft
appendages. LFSAH should demonstrate the deployment capability of a number of
hinge configurations on
STS-93.